Ultrasensitive Detection of TNT in Soil, Water, Using Enhanced Electrogenerated Chemiluminescence

Authors

Tommie L. L. Pittman, University of Southern Mississippi
Bethtrice Thomson, University of Southern Mississippi
Wujian Miao, University of Southern MississippiFollow

Document Type

Article

Publication Date

1-26-2009

Department

Chemistry and Biochemistry

School

Mathematics and Natural Sciences

Abstract

The ultrasensitive detection of 2,4,6-trinitrotoluene (TNT) was accomplished on the basis of sandwich-type TNT immunoassay combined with electrogenerated chemiluminescence (ECL) technology. Biotinylated anti-TNT species were attached to the surface of 1-μm diameter streptavidin-coated magnetic beads (MB) and 10-μm diameter avidin-coated polystyrene microspheres/beads (PSB) pre-loaded with ECL labels (∼7 billion hydrophobic ruthenium(II) tris(2,2′-bipyridine) (Ru^II) molecules per bead) to form anti-TNT ↔ MB and anti-TNT ↔ PSB(Ru^II) conjugates, respectively. Sandwich-type PSB(Ru^II) ↔ anti-TNT < TNT > anti-TNT ↔ MB aggregates were formed when PSB(Ru^II) ↔ anti-TNT was mixed with anti-TNT ↔ MB conjugates in the presence of analyte TNT and 2.0% bovine serum albumin blocking agent. The newly formed aggregates were magnetically separated from the aqueous reaction media and dissolved in acetonitrile containing 0.10 M tri-n-propylamine ECL coreactant–0.055 M trifluoroacetic acid–0.10 M tetrabutylammonium tetrafluoroborate electrolyte. ECL as well as cyclic voltammetric measurements were carried out with a potential scan from 0 to 2.8 V vs Ag/Ag⁺, and the integrated ECL intensity was found to be linearly proportional to the analyte TNT concentration over the range of 0.10–1000 ppt (pg mL⁻¹). The limit of detection (≤0.10 ± 0.01 ppb) is about 600× lower as compared with the most sensitive TNT detection method in the literature, and the absolute detection limit in mass (∼0.1 pg) is only ∼0.5% of that from mass spectroscopy. The approach coupled with the standard addition method was applied to measure the TNT contaminations in soil and creek water samples collected from a military training base.

Publication Title

Analytica Chimica Acta

Volume

632

Issue

2

First Page

197

Last Page

202

Recommended Citation

Pittman, T. L., Thomson, B., Miao, W. (2009). Ultrasensitive Detection of TNT in Soil, Water, Using Enhanced Electrogenerated Chemiluminescence. Analytica Chimica Acta, 632(2), 197-202.
Available at: https://aquila.usm.edu/fac_pubs/8933